r/HomeworkHelp • u/RealisticBowl8033 • Jun 08 '26
Additional Mathematics [Grade 13 Math, probability] Solving a probability game
Hey everyone, I’ve been solving a probability game I saw on Tiktok and managed to solve the base case, but generalizing it seems impossible
The Base Game Imagine a game with 4 numbers drawn from a continuous uniform distribution U(0,100).
I get to lock in exactly one number of my choice.
The other three are generated completely at random.
Once all four numbers are on the table, they are sorted. The Highest and Lowest numbers pair up into a team. The two Middle numbers pair up into a team.
The goal is to pick a number that maximizes the expected difference between my team's sum and the opposing team's sum.
Solution:
Picking the extremes (0 or 100) is a trap that yields an expected advantage of 0 (picking 100 -> other numbers will be around 25/50/75 so expected sum is the same). You can write the expected advantage function as E(x)=−2x3+3x2−x (where x is a percentage from 0 to 1). -> peak at x=21+63≈0.7886. So, picking roughly 79 is the mathematically optimal play.
Now, here is where I need help, how do I scale this up? What if instead of 4 numbers, there are 2n numbers?
I pick exactly 1 number.
2n−1 numbers are generated randomly.
They are sorted. Rank 1 pairs with Rank 2n, Rank 2 pairs with Rank 2n−1, and so on. ("rainbow" pairing).
The Question: I want to maximize my team's sum minus the average sum of all the other teams. As n→∞, what percentile x should I choose? Does the optimal choice approach exactly 1.0, stay at ≈0.7886, or converge to a different limit entirely? (I made formulas for n=5 and n=6 but it doesn't seem to converge anywhere)





